3VZH:
reference: Conservation and Variability in the Structure and Function of the Cas5d Endoribonuclease in the CRISPR-Mediated Microbial Immune System., Koo Y, Ka D, Kim EJ, Suh N, Bae E, J Mol Biol. 2013 Oct 23;425(20):3799-810. doi: 10.1016/j.jmb.2013.02.032. Epub, 2013 Mar 7. PMID: 23500492

This OCA Structure page
uses Jmol, developed by the Jmol Development Team (documentation).